Clinical characteristics and 12-month outcomes of patients with myocardial infarction with nonobstructive coronary arteries before and during the COVID-19 pandemic.

Introduction: SARS‑CoV‑2 infection is associated with an increased risk of thromboembolic complications. Thromboembolism is one of the possible causes of myocardial infarction with nonobstructive coronary arteries (MINOCA).
Objectives: We aimed to compare the characteristics and 12‑month clinical outcomes of patients with MINOCA treated before and during the COVID‑19 pandemic.
Patients and Methods: We retrospectively analyzed data of 51 734 patients with acute myocardial infarction registered in the nationwide Polish Registry of Acute Coronary Syndromes database in 2019 and 2020. The final study group included 3178 patients with MINOCA. We compared the baseline characteristics, management strategies, and 12‑month clinical outcomes of the MINOCA patients treated before (2019) and during the COVID‑19 pandemic (2020).
Results: The rate of MINOCA was higher in 2019 than in 2020 (6.3% vs 5.9%; P = 0.03). The only difference between the groups was a higher hypercholesterolemia rate before the pandemic (33.9% vs 28.2%; P <0.001). In‑hospital stroke was observed more frequently during the pandemic (0% vs 0.3%; P = 0.01), whereas other in‑hospital complications were similar between the groups. Most patients were discharged on aspirin (85.6%), a β‑blocker (73.1%), an angiotensin‑converting enzyme inhibitor / angiotensin receptor blocker (70.2%), and a statin (62.7%), but only 50.6% of the participants received a P2Y12 inhibitor. There was no difference in 12‑month all‑cause mortality between the patients with MINOCA treated before and during the pandemic (9.2% vs 11%; P = 0.09).
Conclusions: We observed a lower percentage of MINOCA cases and higher in‑hospital stroke rates in the MINOCA patients treated during the COVID‑19 pandemic (2020). The possible association between worse clinical outcomes of the MINOCA patients treated during the pandemic and the increased risk for thromboembolic complications of SARS‑CoV‑2 infection needs further evaluation.